Conventionally, printheads and other droplet emitters have always been manufactured separately from the control circuitry. Printheads or droplet emitters are then aligned or affixed to the circuitry during manufacturing to produce a commercial product. Unfortunately, as density or fineness increases, the number of connections between the printhead and the circuitry rises to such an extent that proper alignment incurs a high manufacturing cost overhead. Indeed, the cost is so high that that Epson™, Cannon™ and other manufacturers are forced to sell the printhead as part of the printer rather than as part of the disposable cartridge.
HP™, Lexmark™, and Dell™ address this problem differently, by including a multiplexing circuit inside the printhead. This reduces the number of lines to be connected from over 400 to less than about 60, which is sufficiently low to allow inclusion within the printhead in a disposable ink cartridge. But then the ink cartridge is quite expensive.
What is needed is an inexpensive way of manufacturing low cost printheads (and other fine droplet emitters), where the printhead can be produced as part of the control circuitry. Here, however, a problem arises where the circuitry needs to be flexible. Many embodiments of flex-circuits are known, but they are not readily available with sufficiently fine lines to integrate with a printhead.
There are entirely additive technologies for printing fine lines on polyimide (e.g., Kapton™) or other flexible substrates. Descriptions of various aspects of that technology are set forth in U.S. Pat. No. 6,991,876, U.S. Pat. No. 6,548,122, U.S. Pat. No. 590,988, U.S. Pat. No. 5,846,615, U.S. Pat. No. 5,894,038, U.S. Pat. No. 5,980,813, US2006/0011544, US2004/0091774. These and all other extraneous materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.
It has not, however, been appreciated that those techniques can be used advantageously to produce flexible circuit and printhead portions of an integrated device.